Diffusion plate and grate assembly for a gas burner

ABSTRACT

A gas burner and grate combination includes a gas burner constructed for being operated at least at a high intensity level and at a low intensity level. A grate is located relative to the gas burner for supporting a cooking utensil thereon. A diffusion burner plate is located above the gas burner spaced from a cooking utensil when a cooking utensil is positioned on the grate. The diffusion burner plate is of a size such that when the gas burner is operated at a high intensity level the flame length is long enough to reach beyond the edges of the diffusion burner plate, and when the gas burner is operated at a low intensity level, the flame is contained under the diffusion burner plate such that heating of the cooking utensil occurs by radiation. In a further aspect, a cooktop includes the described gas burner and grate combination.

FIELD OF THE INVENTION

The present invention relates to a combination gas burner and grate assembly with a diffusion burner plate assembled therewith for limiting heat transfer to a cooking utensil such as a pot when the burner is operating at low intensity levels. This arrangement eliminates hot spots typically created by low intensity level burners, while having little to no effect on heat transfer at high intensity levels.

BACKGROUND OF THE INVENTION

Current cooktops employing gas burners have been used commercially and residentially for a number of years. As the construction of such cooktops, both as standalone, built-in, slide-in or drop-in cooktop appliances as well as a part of free standing ranges has evolved, the amount of energy generated by such cooktops has increased, both when employed at the lowest burner intensity settings, as well as at the highest burner intensity settings. In fact, cooktops designed for residential use today are approaching the capabilities of commercial units, including generation of the high BTU's possible with such commercial units. This has led to a number of problems when burners on such cooktops are used at lower intensity levels, or at the lowest intensity levels, for example, for simmering food items in cooking utensils such as pots.

More specifically, the problem with the use of such burners at low intensity levels is that there is not a uniform distribution of energy due to relatively short flame length and thus, this generally creates selected hot spots in the cooking utensil while attempting specialized cooking operations such as simmering. As a result, simmering does not occur uniformly and portions of the food being cooked may tend to burn or to be cooked excessively, while other portions are not sufficiently cooked.

In the past, numerous attempts have been made to distribute the energy from gas burners in a more uniform manner. One attempt to do so involves placing a diffuser plate directly on the grate with which a burner is used so that the flames coming from the burner are not allowed to contact the cooking utensil. Such an approach avails itself of the fact that heating of the cooking utensil occurs by conduction which occurs as a result of the flames impinging on the diffuser plate and causing heat to be conducted through the diffuser plate to the cooking utensil. This approach is suitable for a low burner flame operation, but is not suitable for a high flame operation.

More specifically, if the diffuser plate is made too thick and is separated sufficiently from the burner as a result of being placed above the grate, there may be insufficient energy transfer to the cooking utensil when the burner is operated at low intensity levels. Conversely, if the diffuser plate is made too thin, due to the imperfect nature of how heating of the diffuser plate and conduction occurs, there could still result a number of localized hotspots, which also occur when a diffuser plate is not used. More specifically, depending on materials selected for the diffuser plate, conduction is generally not uniform. While there may be materials from which the diffuser plate could be made in which conduction could more evenly occur, such materials would make construction of the diffuser plate prohibitively expensive.

One alternative approach has been to provide a jet impingement/radiation plate which functions to transfer heat from a burner to a cooking utensil both by radiation and by jets produced by jet holes in the plate. Such a plate is generally mounted directly below a grate of a burner and while attempting to create radiant heat, still has the problems of creating hotspots particularly because conduction occurs from the plate to the grate directly and therefrom to the cooking utensil. Similarly, the fact that hot combustion products, i.e., burning gas, pass through the many openings in the plate to impinge upon the bottom of the cooking utensil also causes the problem of localized hotspots.

Other approaches have involved various deflector arrangements in an attempt to enlarge the area of flame impinging on cooking utensil. All of these approaches suffer from the afore-mentioned problems.

These and other problems of the prior art are avoided in accordance with the present invention in which a system is provided for limiting heat transferred to a cooking utensil when a burner is operating at low intensity levels, and providing heating at the lower intensity levels substantially through radiation with little or substantially no conduction occurring, while having little or no effect on heat transfer when the burner is operated at high intensity levels.

BRIEF SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, there is provided a gas burner and grate combination, which includes a gas burner constructed for being operated at least at a high intensity level and at a low intensity level. As will be appreciated by those of ordinary skill in the art, such burners are also capable of being operated at intermediate levels between the highest and the lowest intensity level depending on the amount of opening of a valve providing gas to the burner.

A grate is located in association with the gas burner for supporting a cooking utensil thereon and for having food therein cooked through operation of the gas burner. Such a cooking utensil can take various forms including pots, pans and various other containers for food. A diffusion burner plate is located above the gas burner at a location for being spaced from a cooking utensil when a cooking utensil is positioned on the grate. The diffusion burner plate is of a size such that when the gas burner is operated at a high intensity or at levels, which are higher than the lowest intensity level as appropriate, the flame length is long enough to reach beyond the diffuser burner plate. When the gas burner is operated at a low intensity level, i.e., typically at the lowest intensity level and selected levels higher than the lowest level, depending on the size selected for the diffuser burner plate, the flame is contained under the diffusion burner plate and heating of the cooking utensil occurs substantially by radiation. This avoids hot spots, which occur at low intensity levels. Alternately, there can be a central opening or hole in the diffusion burner plate which can provide both radiation and a controllable amount of heat transfer directly to the cooking vessel through the central opening.

The diffusion burner plate can be constructed integral to the grate or with means for being removably attached to the grate such as, for example, with clips. The removably attached diffusion burner plate can be utilized with burners that were not originally fitted or made with a diffusion burner plate. Further the diffusion burner plate can just loosely rest on fingers provided on the grate, so the diffusion burner plate easily can be lifted off of the grate for cleaning.

The diffusion burner plate can be constructed in various forms to conform to the shape of the burner or to be different from the shape of the burner. The diffusion burner plate can be made of metal or a ceramic material and can be of different shapes such as concave or convex. For example, in the case of a star shaped burner the diffusion burner plate can be star shaped or circular. The diffusion burner plate can also be perforated, but not sufficiently to allow flames to reach through the burner plate to the cooking utensil, with the exception of ones designed with the central opening therein.

In a yet still further aspect, the invention relates to a cooktop, which includes at least one gas burner and grate combination with a diffusion burner plate as previously described. The cooktop preferably includes a plurality of gas burners and a corresponding plurality of grates, or a single large grate, corresponding to the plurality of burners and with at least one diffusion burner plate on one of the gas burner and grate assemblies. In a yet still further aspect, the cooktop can include a plurality of diffusion burner plates corresponding to the plurality of gas burners. By the term plurality is meant at least two, and in most typical cooktop constructions, at least four and in some cases six to eight aforementioned combinations.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view of the gas burner and grate combination illustrating the diffuser burner plate of the present invention mounted thereon;

FIG. 2 is a top plan view of the gas burner and grate combination of FIG. 1;

FIG. 3 is a side partial cross-sectional view of the gas burner and grate combination of FIG. 1 showing the diffusion burner plate with the gas burner in operation;

FIG. 4 is a side partial cross-sectional side view of the gas burner and grate combination showing for illustration purposes only the diffusion burner plate operating as one half of the operation and with the other half without the diffusion burner plate, both with the gas burner in operation;

FIG. 5 is a side partial cross-sectional view of the gas burner and grate combination showing another embodiment of the diffusion burner plate with a central opening and with the gas burner in operation;

FIG. 6 is a side partial cross-sectional view of an alternate embodiment in which the diffusion burner plate is removably mounted to the grate by a plurality of clips; and

FIG. 7 is perspective view of a cooktop having multiple gas burners and illustrating a pair of gas burner and grate combinations, each with a diffusion burner plate of the present invention mounted thereon.

DETAILED DISCUSSION OF THE INVENTION

FIGS. 1 and 2 illustrate a gas burner and grate combination 11 in accordance with the present invention. A gas burner 13 is associated with a cooking utensil support such as a grate 15, as conventionally used on gas cooktops, as is well known by those of ordinary skill in the art. A diffusion burner plate 17 is disposed between the gas burner 13 and the grate 15 and attached to the grate 15. The diffusion burner plate 17 is sized or dimensioned so that gas flames (see FIG. 3) emanating through apertures 19 of the gas burner 13, when the burner 13 is operated at the lowest or lower intensity levels, will not extend beyond a peripheral edge 20 of the diffusion burner plate 17 and instead will impinge directly on the bottom of the diffusion burner plate 17 to achieve radiant heating of a cooking utensil such as a pot which may be placed on the grate 15 (see FIG. 3), without any substantial amount of conduction of heat to the cooking utensil. By the term lowest or lower intensity levels is meant low heat or the approximate lowest flame intensity for the burner 13 to maintain.

FIG. 3 illustrates one embodiment of the present invention and its operation at both high fire 23 on the left and low fire 21 on the right. This operation is only for purposes of illustration as the gas burner 13 in normal operation emits a substantially uniform flame around a periphery 22 thereof. In this Figure, the diffusion burner plate 17 is directly connected to the grate 15, preferably below or at the lowest level of the grate 15 so as to create an air gap 27 between the diffusion burner plate 17 and the cooking utensil 25. When the gas burner 13 is turned on at the lowest or a low intensity level (low fire illustrated on the right side of FIG. 3), the flames 21 resulting from gas discharged through the ports 19 are contained beneath the diffusion burner plate 17. Heating of the cooking utensil 25 occurs as a result of conduction 29 which heats up the diffusion burner plate 17 to cause heat 31 to radiate through the air gap 27 up to the cooking utensil 25 to promote substantially uniform heating, substantially without hotspots of the cooking utensil 25. When the gas burner 13 is turned onto a high or higher intensity level (high fire illustrated on the left side of FIG. 3), the length of the flames extend as flames 23 beyond the edge 20 of the diffusion burner plate 17 and therefore the diffusion burner plate 17 does not interfere with direct heating 34 of the cooking utensil 25 at the higher intensity levels. By the term high or higher intensity level is meant high heat or the approximate highest flame intensity for the burner 13 to maintain in a normal operation.

It will be appreciated that some conduction 29 occurs through the grate 15 to the diffusion burner plate 17 as a result of the diffusion burner plate 17 being directly attached thereto, but this is a substantially minimal effect.

In the embodiment of FIG. 3, and FIGS. 1 and 2, the diffusion burner plate 17 is shown permanently mounted to the grate 15 by any means appropriate as will be readily apparent to those of ordinary skill in the art. The diffusion burner plate 17 can be permanently mounted to the grate 15 by numerous methods, such as welding, mechanical fasteners, such as screws or rivets or a mechanical interlocking feature like a bayonet twist. The diffusion burner plate 17 also can be integrally made or formed with the grate 15, such as by casting.

In accordance with FIG. 4, for illustration purposes only, the diffusion burner plate 17 is illustrated operating as one half of the operation 30 (left side) and with the other half of the operation 32 (right side) a standard burner operation without the diffusion burner plate 17, both with the gas burner 13 in a simmer operation producing the low flame 21. In the diffusion burner plate 17 operation 30, heat 36 from the flames 21 is convectively transferred to the diffusion burner plate 17, which in turn radiates heat 31 from the diffusion burner plate 17 to the utensil 25. In the standard operation 32, heat 38 from the flames 21 is convectively transferred directly to the utensil 25, with minimal conductive heat loss. Both operations 30 and 32 have minimal conductive heat loss into the grate 15.

In accordance with FIG. 5, another embodiment of the present invention is illustrated, in this case, the diffusion burner plate 17′ includes a central opening 33. The central opening 33 is dimensioned to provide some direct convective heat transfer through the diffusion burner plate 17′ to the utensil 25. This may enhance the heating of a central portion 35 of the utensil 25 and also can reduce the weight of the diffusion burner plate 17′.

Although the diffusion burner plates 17, 17′ have been described as being attached permanently or substantially permanently to the grate 15, the diffusion burner plates 17, 17′ also can be separate from the grate 15 and can just rest on the grate 15. This also is illustrated in FIG. 5, where the diffusion burner plate 17′ is a separate element and rests on a plurality of fingers or lips 42 which are secured to or formed with the grate 15. The fingers 42 can be welded or integrally formed with the grate 15. Although not illustrated, the diffusion burner plate 17′ also could have projections formed thereon which allow the diffusion burner plate 17′ to rest on the grate 15. In that case the grate 15 would not be formed with the fingers 42. In either case, the diffusion burner plate 17′ easily can be removed from the grate 15 just by lifting the diffusion burner plate 17′ off of the grate 15, such as for cleaning purposes.

In accordance with FIG. 6, an alternative construction of the present invention is shown, in this case, the diffusion burner plate 17 is mounted onto the grate 15 by way of a plurality of clips 33 which can allow for removal of the diffusion burner plate 17 in selected instances as may be appropriate for the user. Also the clips 33 allow the diffusion burner plate 17 to be added to cooktops to which it was not provided for as a retrofitting of the cooktop. While the clips 33 are illustrated, as will be readily apparent to those of ordinary skill in the art, other equivalent means for mounting the diffusion burner plate 17 can be employed. What is important is that the air gap 27 between the diffusion burner plate 17 and the bottom of any utensil 25 placed on the grate 15 is maintained. Further the air gap 27 is sized to provide the most efficient radiant heating of utensils 25 at low intensity levels of operation of the gas burner 13. The air gap 27 and the diameter of the diffusion burner plate 17 are optimized for the diameter of specific burners 13, BTU rate, the design of the burner ports 19, type of fuel, etc. Generally the diameter of the diffusion burner plate 17 is the most critical factor as long as the air gap 27 is present. Generally an air gap 27 on the order of at least two (2) to three (3) millimeters is sufficient for operation with the diffusion burner plate 17. The upper limit of the air gap 27 depends upon the desired operation of the cooktop and the type of burner utilized.

In a yet still further aspect of the present invention, there is shown in FIG. 6 a cooktop 37 having multiple gas burners 13 thereon and a single integral grate 15 used for all the gas burners 13. Such a cooktop 37, as previously described, can be a standalone cooktop with the burners 13 mounted in a cabinet (not illustrated), or can be part of a combination standalone range with an oven (not illustrated). Typically, such cooktops include at least four burners and in some cases up to six or eight burners. The cooktop 37 can be assembled with only one diffusion burner plate 17 or with multiple diffusion burner plates 17 either removably attached or permanently affixed thereto as previously described.

As implemented, the diffusion burner plate 17 of the present invention reduces the net effect of energy transfer to the cooking utensil 25 when a gas burner 13 is operated at low intensity levels without substantially reducing the net energy transfer when the gas burner 13 is operated at high intensity levels.

As previously discussed, the diffusion burner plate 17 does not come into contact with the cooking utensil 25 so that heat transferred to the utensil 25 is substantially only by radiation from the diffusion burner plate 17 without substantial conduction transfer. As a result, hot spots typically found on low intensity settings of the cooktop are avoided by even distribution of the energy over a larger surface of the cooking utensil 25.

In various alternative constructions, the diffusion burner plate 17, 17′ can be perforated as previously discussed. The diffusion burner plate 17, 17′ can be thick or thin in design as will be readily apparent to those of ordinary skill in the art, and optimized for operation with a selected cooktop and/or gas burner and grate combination with which it is to be used. In terms of shape, the diffusion burner plate 17, 17′ can be substantially flat, convex or concave in shape as appropriate to optimize performance. Another advantage of the use of the diffusion burner plate 17, 17′ is the operation is independent of the type of gas burner utilized.

In terms of material utilized to make the diffusion burner plate 17, it can be made from metal or from ceramic or from other appropriate material as will be readily apparent to those of ordinary skill in the art. The diffusion plate burner 17 diameter may be optimized in size to allow a range of settings for the lower intensity settings for the gas burner 13. The diffusion burner plate 17 can conform to the shape of the gas burner 13 with which it is used or can be of a different shape. For example, a round gas burner 13 may have a round diffusion burner plate 17 and a star shaped gas burner 13 may have a star shaped diffusion burner plate 17. In other cases the diffusion burner plate does not conform to the shape of the gas burner 13, for example, a round gas burner 13 could have a star shaped diffusion burner plate 17. Other examples of shapes include triangles or squares. Any of shapes of the diffusion burner plate 17 can include the central aperature 33.

Having thus generally described the invention, the same will become better understood from the appended claims in which it is set forth in a non-limiting manner. 

1. A gas burner and grate combination, comprising: a gas burner constructed for being operated at least at a high intensity level and at a low intensity level; a grate located relative to said gas burner for supporting a cooking utensil thereon, for having food therein cooked through operation of the gas burner; a diffusion burner plate located above the gas burner at a location for being spaced from a cooking utensil when a cooking utensil is positioned on said grate forming an air gap there between, and of a size wherein when the gas burner is operated at a high intensity level, the flame length is long enough to reach beyond the diffusion burner plate, and when the gas burner is operated at a low intensity level, the flame is contained under the diffusion burner plate and heating of the cooking utensil occurs by radiation thereby avoiding hot spots which occur at low intensity levels.
 2. The gas burner and grate combination of claim 1, including said diffusion burner plate constructed integral with said grate.
 3. The gas burner and grate combination of claim 1, including said diffusion burner plate including means for being removably attached to said grate.
 4. The gas burner and grate combination of claim 1, including said gas burner having a burner cap and said diffusion burner plate located above said burner cap.
 5. The gas burner and grate combination of claim 1, including said diffusion burner plate including a central opening or aperture therein.
 6. The gas burner and grate combination of claim 1, including said diffusion burner plate is formed in a solid element.
 7. The gas burner and grate combination of claim 1, including said diffusion burner plate is formed with perforations therein.
 8. The gas burner and grate combination of claim 1, including said diffusion burner plate shaped to conform to the shape of the gas burner.
 9. The gas burner and grate combination of claim 1, including said diffusion burner plate made from one of a metal and a ceramic material.
 10. The gas burner and grate combination of claim 1, including said diffusion burner plate formed of a thickness and width selected for causing simmering of foodstuffs in a cooking utensil when said gas burner is operated at an intensity level where the length of the flames from said burner does not extend beyond an outer edge of said diffusion burner plate.
 11. The gas burner and grate combination of claim 1, including fingers extending from said grate for supporting said diffusion burner plate thereon.
 12. The gas burner and grate combination of claim 1, including said diffusion burner plate shaped to not conform to the shape of the gas burner.
 13. The gas burner and grate combination of claim 1, including said diffusion burner plate is located sufficiently spaced from a cooking utensil when a cooking utensil is placed on said grate to ensure that substantially all heating occurs by radiation with substantially no heating by conduction occurring.
 14. The gas burner and grate combination of claim 1, including said diffusion burner plate formed in one of a substantially flat, a concave or a convex shape.
 15. A cooktop, comprising: at least one gas burner constructed for being operated at least at a high intensity level and at a low intensity level; at least one grate corresponding to said at least one gas burner located relative to said at least one gas burner for supporting a cooking utensil thereon, for having food therein cooked through operation of the gas burner; at least one diffusion burner plate located above the gas burner at a location for being spaced from a cooking utensil when a cooking utensil is positioned on said grate forming an air gap there between, and of a size wherein when the gas burner is operated at a high intensity level, the flame length is long enough to reach beyond the diffusion burner plate, and when the gas burner is operated at a low intensity level, the flame is contained under the diffusion burner plate and heating of the cooking utensil occurs by radiation thereby avoiding hot spots which occur at low intensity levels.
 16. The cooktop of claim 15, including said diffusion burner plate constructed integral with said grate.
 17. The cooktop of claim 15, including said diffusion burner plate including means for being removably attached to said grate.
 18. The cooktop of claim 15, including said gas burner having a burner cap and said diffusion burner plate located above said burner cap.
 19. The cooktop of claim 15, including said diffusion burner plate including a central opening or aperture therein.
 20. The cooktop of claim 15, including said diffusion burner plate is formed in a solid element.
 21. The cooktop of claim 15, including said diffusion plate burner is formed with perforations therein.
 22. The cooktop of claim 15, including said diffusion burner plate shaped to conform to the shape of the gas burner.
 23. The cooktop of claim 15, including said diffusion burner plate made from one of a metal and a ceramic material.
 24. The cooktop of claim 15, including said diffusion burner plate formed of a thickness and width selected for causing simmering of foodstuffs in a cooking utensil when said gas burner is operated at an intensity level where the length of the flames from said burner does not extend beyond an outer edge of said diffusion burner plate.
 25. The cooktop of claim 15, including said diffusion burner plate is formed in one of a substantially flat, a concave or a convex shape.
 26. The cooktop of claim 15, including said diffusion burner plate shaped to not conform to the shape of the gas burner.
 27. The cooktop of claim 15, including said diffusion burner plate is located sufficiently spaced from a cooking utensil when a cooking utensil is placed on said grate to ensure that substantially all heating occurs by radiation with substantially no heating by conduction occurring.
 28. The cooktop of claim 15, including a plurality of gas burners and a plurality of said grates corresponding to said plurality of burners.
 29. The cooktop of claim 29, including a plurality of diffusion burner plates corresponding to said plurality of gas burners. 